Web tensioning device



A- APICELLA WEB TENSIONING DEVICE Dec. 23, 1969 Filed Oct. 11. 196?ANI'HUN) Amati/.4

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United States Patent U.S. Cl. 226- 8 Claims ABSTRACT OF THE DISCLOSURE Aweb tensioning device to automatically control the tension on a web asit is fed into and through a machine for processing and taken up readilyadaptable for intermittent progressive step operations providing alever, one end of which impinges upon the web, the lever in pivotingactuating web payout with the web payout controlled by a pair ofswitches. A first switch pays out the web by actuating the web payoutrollers, the second switch deaciivates the web payout rollers andsubstantially prevents paying out of the web. The switches are actuatedby means carried on the lever which come in contact with the switcheswhen the lever pivots, the lever pivot being dependent upon the take upand payout of the web.

The present invention relates to a web tensioning device.

In many fields, but particularly in the printing field where a web ofmaterial is required to be fed through a machine for processing properregistration is critical or substantial waste by way of misregistrationmay occur.

For example, many printing operations are progressive step operationssuch as found in label making where a web as processed is subjected tovarious environments during certain stages of production such asheating, embossing, printing and cutting, and in order that there beproper registration it is necessary that the web enter each of thesestages under desired tension so as to maintain the web in a givenspacial relationship with the various tools and dies employed.

Problems of proper registration are accentuated in cases wherereciprocating printing equipment is employed since there is added to theproblem of registration during a progressive step operation, the problemof the intermittant or stop and go feeding of the web through itsvarious processing stages.

In order to overcome the foregoing problem, not only in the printingfield, but in all fields where a web is being run through a machine orprocess and proper registration is necessary, various devices have beenemployed in an attempt to provide the necessary registration.

In some instances these devices took theform of regulating means whichcontrolled the speed of the web payout and/or attempted to synchronizethe web payout with the processing steps. These devices were inefficientor ditficult to regulate especially in intermittant type operationsbecause of the stop and start nature of the operation. In addition theweb registration was attempted to be controlled by a synchronization ofpay out to processing steps with little or no provision for otherwisemaintaining a constant tension on the web.

Registration of a web by tensioning alone or in combination with otherequipment also had many inherent difliculties. While the proper tensionmight be found for a particular web after determining the strength andstretch characteristics of the web, the devices employed for suchtensioning were generally limited to a web of given norm characteristicsand the resetting of the tension for webs of differing characteristicsespecially where such tensioning mechanism was interrelated to other3,485,426 Patented Dec. 23, 1969 regulating systems was a somewhatcomplicated operation.

According to the present invention a web tensioning device is providedwhich provides constant tension on the web both during payout and restand allows for a single speed payout regardless of the web and webprocessing equipment employed.

The web tensioning device of the present invention automaticallycontrols the tension on the web as it is fed into and through a machinefor processing and taken up and is readily adapted for intermittantprogressive step operation.

The web is threaded between a pair of rollers, one of which isactuatable upon a signal to payout the web. The web is then positionedso as to have the weight of a lever arm depend thereon. As the web istaken up during processing the amount of web between the processingmachine and the pay-out rollers lessens, and this shortening of the weblength pivots both ends of the lever about its fulcrum. At a selected]point during take up the lever comes in contact with first switch meansto actuate the motor which controls the payout rollers causing thepayout rollers to feed web out. As the web is payed out the weight ofthe end of the lever arm which depends upon the web maintains the web inconstant tension and pivots the lever. At a selected point during payoutthe lever comes in contact with second switch means which deactivatesthe payout rollers. The tensioned web is continually taken up and payedout as required by the processing machine.

Proper control of the payout motor switches is maintained by provisionof switch actuation means on the lever at a point on the lever of aradial distance greater than the greatest distance from the fulcrum ofthe lever to the edge of the 'fulcrum support in the area of theswitches, and by having the actuating arms of the switches projectingbeyond the edge of the fulcrum support so as to lie in an intersectingplane with the switch actuation means, the are described by the pivotinglever bringing the switch actuation means in contact with the switcharms at selected points along such arc.

Although such novel feature of features believed to be characteristic ofthe invention are pointed out in the claims, the invention and themanner in which it may be carried out may be further understood byreference to the description following and the accompanying drawings.

FIG. 1 is a side elevation of a device of the present invention asemployed with a label making machine.

FIG. 2 is a side elevation of a device of the present invention.

FIG. 3 is a perspective view partly broken away of a device of thepresent invention.

FIG. 4 is a detailed sectional view of the payout roller driver means.

Referring now to the figure in greater detail, where like referencenumbers denote like parts in the various figures.

As shown in FIGS. 1-3 the tensioning apparatus 1 is interposed betweenthe web spool 2; and the working structure shown schematically as alabel printing, stamping, embossing and cutting machine 3 which may runa second web 4 at right angles to the web 5 in processing, and is in thenature of the apparatus described in my U.S. Patent No. 3,289,573 datedDec. 6, 1966.

The tensioning apparatus 1 generally comprises a frame interposedbetween the web spool 2 and the label machine 3, the frame preferablyhaving spaced apart vertical side walls 6. As shown in FIGS. 1-3 and ashereinafter more fully described, the edge of the lower section 14 ofeach of the side walls 6 facing the web spool 2 is preferablysubstantially vertical and the edge of the upper section 15 of each ofthe side Walls 6 facing the Web spool 2 is inclined at angle away fromthe web spool 2.

A drive roller 7 is rotatably mounted between the side walls 6preferably near the upper portion of the walls 6 and a guide roller 8 ispreferably rotatably mounted in parallel vertically closely spaced apartrelationship to the drive roller 7 so that the web threaded between therollers 7, 8 will be impinged therebetween and substantially preventedfrom paying out until rotation of the rollers 7, 8. It is readilyapparent that the positions of the rollers 7, 8 may be reversed so as tohave the feeding, or drive roller 7 as the upper roller and the guideroller 8 as the lower roller.

A lever 9 is pivotally mounted between the side walls 6, the fulcrum 10of the lever 9 preferably located below the rollers 7, 8. The lever 9 asshown extends through the frame defined by the walls 6 with a portion ofthe lever 9 between the web spool 2 and the walls 6 projecting outwardfrom between the walls 6. Although as shown in FIGS. 1-3 both endportions of the lever 9 extend outward of the frame defined by the walls6, if desired, the walls 6 may be of sufficient width so that the lengthof the lever 9 between the fulcrum 10 and the work piece 3 may be maskedbetween the walls 6.

The lever 9 is preferably an openwork frame of two arms 11interconnected at a point near the outer ends of the arms 11, suchinterconnection preferably made by a rotatably mounted guide 12.

Each arm 11 is preferably provided with a looped end portion 16 which isdisposed between the fulcrum 10 and the web spool 2, each arm 11 therebybeing substantially J-shaped.

In normal position, the lever 9 is balanced so that greater weight ispresent at the portion of the lever 9 between the fulcrum 10 and thework piece 3 the lever 9 thereby pivoting so as to be inclined with theportion of the lever 9 between the fulcrum 10 and the work piece 3 belowthe the horizontal.

While the desired normal position of the lever 9 is inclined asaforementioned, the requisite force to be applied by such inclined lever9 is dependant upon a combination of variant factors, such as theresiliency of the web 5 and the strength of the take-up of Web 5 by thework piece 3. As shown in FIGS. 1-3 selective control of the lever 9 maybe readily provided by the use of weights 17 which may be provided invarious numbers or weight on both or either side of fulcrum 10. Thelooped end portion 16 of the lever 9 is readily amenable to accommodateweights 17 along the entire length of the shorter leg of the J leavingthe lower section below the shorter leg of the 1 free to carry a portionof the payout controls shown as plate 18.

The plate 18 is mounted on one of the arms 11 so as to project outwardtransversely from the arm 11 so as to lie in an intersecting plane withthe edge of the side wall 6. The plate 18 is mounted along arm 11 at apoint of a greater radial distance from the fulcrum 10 than the radialdistance from the point of meeting of the vertical edge and the inclinededge of the wall 6. In such manner, during the pivoting of the lever 9the are described by the lever 9 at the point of affixation of the plate18 will carry the plate 18 from a point above the inclined edge to apoint above or along the vertical edge.

As shown in FIGS. 2 and 4 the payout roller 7 is actuatable to rotationby a motor 19. The actuation of the motor 19 is controlled by switches20 and 21 respectively, the switches 20, 21 in the nature ofmicroswitches having spring contacts 22.

The switches 20, 21 are disposed along the side wall 6, with the contact22 of switch 20 proecting above the inclined edge of wall 6 and thecontact 22 of switch 21 projecting beyond the vertical edge of wall 6,both contacts lying in a plane which will intersect plate 18 uponpivoting of the lever 9.

Upon actuation, by plate 18 causing contact 22 of switch 21 to makecontact, motor 19 is actuated and payout roller 7 is actuated to feedout web 5. When plate 18 actuates switch 20 by causing the contact 22 ofswitch 20 to make contact, the motor 19 is deactuated and the circuit ofswitch 21 is broken thereby stopping further payout of the web 5.

In operation, the web 5 taken from web spool 2 is threaded betweenrollers 7, 8, threaded under guide 12 and thence to the Work piece 3 tothe take-up roller 23. The web 5 is maintained tensioned by the guide 12bearing downward upon the web 5. As the web is taken up, the take-uppull of the web will cause the lever 9 to pivot upward. The plate 18will pivot downward until plate 18 actuates switch 21. Upon actuation ofswitch 21 web 5 will be payed out by rollers 7, 8 thereby causing theguide 12 end of the lever 9 to pivot downward. This will bring plate 18into contact with switch 20 which will deactuate the motor 19, theswitch 20 causing payout to cease.

The payout of the web 5 through rollers 7, 8 when actuated isselectively timed so as to be at least equal to, and preferably slightlygreater than the speed of the take-up 23. In this manner the web 5 isconstantly tensioned by the weight of the guide 12 end of the lever 9.

While the fulcrum 10 has been illustrated as being interposed betweenthe web spool 2 and the rollers 7, 8 it is readily apparent that therollers 7, 8 may be mounted separately at a point between the web spool2 and the fulcrum 10 and the supporting structure for the fulcrum 10 asimple arrangement of two vertical supports. Any such arrangements ormodifications provides for a constant tensioning of a web by a lever armduring the reciprocating of the lever, with the reciprocating of thelever a payout control for the Web.

It is to be further understood that the payout speed need only besufiicient to be equal to or to exceed the speed of take-up of the webprocessing machine. In this manner no sophisticated synchronizationequipment for the synchronization of the payout speed to take up speedneed be employed, however if desired the motor 19 may be of the typewhich has various speed settings and in this manner the tensioningdevice of the present invention may be employed interchangeably withvarious web processing equipment having differing take-up speeds, and asshown in FIG. 1 the web tensioning device may be portable and mounted ona wheeled platform 24.

The terms and expressions which are employed are used as terms ofdescription; it is recognized, though that various modifications arepossible.

Having thus described certain forms of the invention in some detail,what is claimed is:

1. A web tensioning device comprising, a lever mounted between a websource and web take up means, said lever including a lever support, aportion of said lever adapted to impinge upon said web to tension saidweb, web payout means adapted to deactivate the feeding out of said web,said web payout means including power means; first switch means adaptedto actuate said power means to feed out said web and second switch meansadapted to deactivate the feeding out of said web, said first and secondswitch means mounted on said support with the contacts of said first andsecond switches at points substantially along a portion of such support,switch actuation means on said lever adapted to actuate said first andsecond switch means upon pivoting of said lever, the taking up of saidweb pivoting said lever to bring said switch actuation means intocontact with said first switch means and the feeding out of said webpivoting said lever to bring said switch actuation means into contactwith said second switch means, said switch actuation means mounted at apoint on said lever of a radial distance greater than the greatestdistance from the ful crum of said lever to the edge of said support inthe area of said switches.

2. The apparatus of claim 1 wherein said web payout means furtherincludes a pair of rollers adapted to impinge a web therebetween, saidweb fed out upon rotation of said rollers.

3. The apparatus of claim 1 wherein said lever comprises an openworkframe including guide means for said web.

4. The apparatus of claim 1 wherein said lever comprises an openworkframe, each side of said frame a substantially J-shaped member havingthe shorter leg of said J opposite said impinging portion of said leverand said impinging portion includes roller means interconnecting saidJ-shaped members.

5. The apparatus of claim 1 wherein said switch actuation means includesa substantially vertical plate mounted on said lever.

6. The apparatus of claim 1 wherein said lever further includesremovably mountable weights adapted to be mounted on said lever atpoints along its length.

7. The apparatus of claim 1 wherein said lever support includes a pairof vertical side walls, the lower portion of at least one of said sidewalls facing said web source being substantially vertical, the upperportion of said last mentioned side wall facing said web source inclinedaway from said web source, said first switch means mounted on said lowerportion of said side wall, said second switch means mounted on saidupper portion of said side wall, and said contact portions of each ofsaid first and second switches disposed beyond the edge of said sidewall.

8. The apparatus of claim 7 wherein said web payout means are mounted onsaid lever support, said web payout means including a pair of rollersmounted between said vertical side walls at a point above said lever.

References Cited UNITED STATES PATENTS 8/1961 Topping 226-43 5/1962Horne et a1. 22643 US. Cl. X.R. 22e 43; 44

